Stereotactic apparatus and methods

ABSTRACT

The present invention includes stereotactic vectors, no electronic calculations and imaging, diagnostic and treatment techniques. The invention also includes machines or instruments using those aspects of the invention. The present invention also includes methods and processes using the devices of the present invention.

This is a divisional application of U.S. application Ser. No.10/172,854, filed Jun. 17, 2002, now U.S. Pat. No. 6,872,213, which is adivisional application of U.S. application Ser. No. 09/394,585, filedSep. 13, 1999, now U.S. Pat. No. 6,406,482. The aforementionedapplications are herein incorporated in their entirety by reference.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to apparatus and methods useful inscientific research and interventional medicine, and useful in thevisualization and analysis of organic tissues and bodies; and toresearch into the cause and symptoms of disease, its diagnosis andtreatment. The invention particularly concerns apparatus which may beadvantageously utilized by a researcher, physician or health careprofessional, in cooperation with cross-sectioning types of medicalimaging equipment, such as computed tomography (CT) imaging equipment ormagnetic resonance (MR) imaging equipment, plain film or fluoroscopy.The invention may be utilized to conveniently and accurately aid intimely (real time), manually, truly, and physically accomplishing thesteps of locating, vectoring, and inserting an object such as a probe orother needle-like medical device at, toward, and in a patient's targetedanatomic feature.

BACKGROUND OF THE INVENTION

This invention relates to magnetic resonance apparatus useful in thevisualization and analysis of organic tissues and bodies, and toresearch into the cause and symptoms of disease, its diagnosis andtreatment.

In the use of magnetic resonance imaging (“MRI”) there is a seriousproblem with interventional procedures. The problem is that the probecannot be seen, and therefore its location is unknown at the momentbefore it is to enter the patient. This is one of the most importantreasons why MRI has not been used extensively for interventionalprocedures.

There are many imaging stereotactic devices currently available. Despitethe incredible power of existing imaging technologies however, very fewprocedures are actually done using the existing technology in a routineclinical setting. There are several reasons for the lack of generalacceptance of these devices in existing markets.

Most of the systems are expensive, and normally this expense cannot bejustified in terms of usage or benefit for the large capital investmentrequired. Physicians and hospitals are generally not prepared in today'seconomic climate to make a large investment for a system that may onlybe used intermittently and may become quickly outdated.

Most existing systems are electronic and use optical and computerinterfaces. The majority of these systems do not function in a real-timesetting, but rather use special post-processed acquired imageinformation. This information is then used to direct the procedure at adifferent time and place.

Many of the systems are imager proprietary or dependent, so it ispossible that only a few units may be able to use a specific technology.Though these systems claim to have very high real-space accuracy, inreality, they have only limited real-space correlation since there is nolive (real-time) imaging to confirm the progress of the procedure.

Most stereotactic units are complex and have multiple components. Someof the systems envelop the patient, for example, through the use of headframes that are bolted directly to the skull. If there is any change inthe components of such a rigid system at the time and place of theactual intervention, the previously obtained information that forms thebasis for the intervention is no longer valid. These systems also relyon gathering many images to direct the operation, rather than needingonly a few. Because of this, the process can be very slow, since a largeamount of data needs to be acquired to direct the process.

A number of existing stereotactic systems utilize fiducials that areplaced on the patient or the stereotactic frame. These areimage-conspicuous markers that are seen in the image space andreal-space. Utilizing this information, the virtual reality spacedepicted on the images is fused with the real-space.

There are a number of devices that attach directly to the scanner, butthese are generally cumbersome and have not been used extensively.

There are also a few systems that use very limited vector trajectories(of only a few angles). These are of little value since the limitednumber of approaches they provide to the target may not be enough toaddress the complicated anatomy, therapeutic devices and goals of avariety of procedures.

Currently there are a number of rapid CT or MRI data acquisition systemsavailable, but they have the disadvantages of being proprietary and ofexposing the patient and operator to increased radiation dosage. TheseCT systems are analogous to fluoroscopy.

There are a few combined CT and fluoroscopic stereotactic systems. Thesehave the potential to be very versatile, but they are complexproprietary systems. There are also a number of open magnet designs, butthese are limited by vendor design. Critical information used to directthe procedure or intervention is based on artifacts from the needle orprobe rather than on accurate real-time real-space information. Theinherent imaging problems created by these artifacts limit the accuracyof these devices. The image quality of the fast imaging systems ingeneral is not as good as routine imaging techniques.

FIG. 1 is a schematic of an enveloping frame that is used for headstereotactic systems of the prior art. The vertical lines 1 of the boxrepresent the vertical struts, the horizontal lines 2 are crossingmembers used to define the section plane, the angled lines 3 representcross-members and the sphere 4 is the target. This frame is bolted orrigidly fixed to the patient and then imaged with many sections. Theinformation gathered is used at a later time and place. Withoutreal-time real-space confirmation during the intervention, there is noabsolute confirmation that the previously determined plan is actuallybeing correctly implemented.

FIG. 2 is a schematic of an image obtained from such a fixed frame rigidsystem. The vertical members 1 are seen at the corners of the square,and the cross-members 3 are used to define the slice location and thetarget 4. There is no intuitive information that an operator can use toconfirm that the information is accurate. Typically, a second system isused to actually execute the procedure at a later time with no real-timereal-space confirmation of the previously obtained plan.

FIG. 3 shows an example of an MRI image 5 showing the use of a fixedframe stereotactic unit used for head imaging. The head 6 appears in thecenter of the image, with the target labeled in the left temporal bone.Also visible are the rods 7 (such as horizontal, vertical andcross-members 1, 2 and 3 shown in FIG. 2) surrounding the skull of thepatient as a fixed device. The information is acquired by takingmultiple images that must be post-processed.

There are a number of limitations to this type of device. Theconstituent support tubes are necessarily relatively large (in order tosupport the static arrangement), and thus cause a certain degree ofinherent error in the system. The image shown is a single image thatprovides no real-time information that an operator might use during animage-monitored procedure. Also, a further error factor arises becausethe tubes are relatively distant from the target site, and the imageitself is not without distortion, making the system distortionsensitive. Also, if the subject is moved, the system cannot be readilyrealigned.

A number of computer-based systems' disadvantages have been mentioned.The most important of these is that they provide no real-timeconfirmation at the actual time of intervention. All of these systemsuse specially acquired post-processed images that assume that thevirtual reality of the previously obtained imaging information and thetrue reality at the time of the actual intervention are identical. Thesesystems are expensive, large, and can only be used in select locations.

There remain problems associated with fast, open, and combinedtechnology systems. All are expensive, vendor specific and, as such, arelimited to only a few sites. They are such complicated systems that anyminor problem can render them useless, for example, if the batteries onan LED stop working. They have limited real-space accuracy since theyhave problems with partial volume averaging and other imaging artifacts.Using these systems it may be difficult to track more than one devicebeing used at a time.

Accordingly, the criteria for an improved stereotactic device included:

1. Accuracy in the form of mm level control and live image confirmation.

2. Ability to make rapid adjustments (preferably by remote control), andthe use of a single image.

3. Flexibility in the form of multiple dimension adjustability, and theaccommodation of a wide variety of probes.

4. Intuitive use through clear, non-computer-generated interpretation ofelectronic image information.

5. Simple construction; a device that may be compact enough to fix theimager on the patient and inexpensively constructed, and may be ofdisposable materials.

6. Applicability independent of site and imaging device.

Accordingly, there remains a need for relatively inexpensivestereotactic devices that may be used with a wide variety of imagingsystems for the performance of varied procedures, and that may be usedwith any number of invasive devices and techniques.

SUMMARY OF THE INVENTION

The present invention includes stereotactic vectors, no electroniccalculations and imaging, diagnostic and treatment techniques.

In broadest terms the stereotactic device of the present inventioncomprises:

A stereotactic device comprising a frame portion attached to: (i) alower plane portion defining a lower plane and comprising a lower vectorpoint, the lower plane portion comprising a template comprising at leastone pair of angled members of an imager-conspicuous material, the atleast one angled member defining an angle of about 53 degrees; and (ii)an upper plane portion; the upper portion comprising: (1) a templatedefining an upper plane and comprising at least one (preferably a pairof) adjacent angled members comprising an imager-conspicuous material,the pair of adjacent angled members aligned such that the pair ofadjacent angled members open in substantially parallel directions, andwherein the angle defined by each of the pair of adjacent angled membersdefines an angle of about 53 degrees, and (2) an alignment structurecomprising an upper vector point adapted to move parallel to the upperplane, so as to be able to define a vector passing through the upper andlower vector points.

It is preferred that the stereotactic device have adjacent angledmembers that include a graduated linear distance position scaleperpendicular to its bisector line.

The principal V patterns of the lower plane position may be accompaniedby additional adjacent V patterns representing equidistant graduationsfrom the respective main “V” limbs.

The lower plane portion may also include a template comprising at leastone pair of angled members of an imager-conspicuous material defining anangle of about 53 degrees. Preferably, two pairs may be used foralignment purposes as described below.

Preferably, the frame portion is adapted to rotate the upper and lowerplane portions with respect to an axis perpendicular to the upper andlower parallel planes. It is further preferred that the frame portionadditionally comprise a graduated position scale to indicate the degreeof rotation of the upper and lower plane portions parallel with respectto one another and in an orthogonal motion.

The stereotactic device of the present invention may optionally includeat least one remote actuator to move the alignment structure within theupper plane (i.e., in the X and Y directions as described herein).Likewise the stereotactic device of the present invention may optionallyinclude at least one remote actuator to rotate the upper and lowerplanes with respect to one another.

In one embodiment, the stereotactic device may have a lower portionprovided with an adhesive base portion.

The stereotactic device of the present invention preferably includes analignment structure in its upper portion that has an interior areathrough which at least portions of a medical instrument may be passed.

The alignment portion may further include an addition V pattern thatbears a graduated linear distance position scale.

The imager-conspicuous material may be selected from any materialappropriate to the imaging device. These may be selected from the groupconsisting of metal members, hollow polymeric members filled with animager-conspicuous material, and polymeric members treated with animager-conspicuous material.

The lower plane portion may be connected to a band (preferably elastic)to be held in place. It may also be connected directly to a sterile orsterilizible drape material to protect the target surface fromcontamination, such as where an adhesive is used to hold it in place.Alternatively, the lower plane portion may be connected to an elasticband, and the elastic band attached to the drape material. Thesearrangements may be formed though the use of stitching, adhesives, orother techniques known in the art for attaching elastic, drapematerials, such as cloths or polymeric materials, and rigid plastics,foam or other solid materials, to one another.

In another embodiment, the stereotactic device of the present inventionmay feature an open architecture to allow the lateral, parallel andorthogonal motion removal of a probe from the device once aligned. Thestereotactic device of this embodiment of the present inventioncomprises: a frame portion attached to: (i) a lower plane portiondefining a lower plane; and (ii) an upper plane portion; the upper planeportion comprising: (1) a template defining an upper plane andcomprising a pair of sufficiently adjacent angled members comprising animager-conspicuous material, the angled members aligned such that theyopen in substantially parallel directions, and wherein the angle definedby each of the pair of adjacent angled members defines an angle of about53 degrees; and (2) an alignment structure adapted to move within theupper plane, so as to be able to align a vector passing through theupper and lower planes. In this embodiment, the alignment structurecomprises a releasable alignment aperture, such as one made up ofopposed flexible members that cooperate to form the alignment aperture.It also includes a frame portion that is open on one side so as to allowan object passed through the alignment structure to be removed in adirection substantially parallel to the upper plane.

In this embodiment the portions of the device, such as the lower portionand the frame portion, may also be as described in their many variationsabove.

The present invention also includes an alignment article for use with animaging device (such as used as a lower template portion as describedherein). The alignment article comprises an imager-transparent memberbearing an imager-conspicuous material in the shape of at least oneangle of about 53 degrees. The imager-conspicuous material may be, forinstance, in the form of printed material or plastic tubes filed withimager-conspicuous material and adhered to the article. In oneembodiment of the article, the alignment article may be planar andadditionally comprise an adhesive base on one side thereof. Preferably,the alignment article has at least one angle additionally comprising agraduated linear distance position scale perpendicular to its bisectorline. The alignment article may also have additional adjacent “V”patterns for equidistant graduation from the respective main “V” limbs.In another embodiment, the alignment article is planar and bearsimager-conspicuous material in the shape of two angles each of about 53degrees and open in substantially parallel directions, and additionallycomprising a perforation in the article passing between the two angles.It is preferred that the alignment article comprises a material capableof being perforated by a syringe needle.

The present invention also includes the methods of placing a probe fromoutside a tissue (or other matter) into a target area located within thetissue (or other matter) using an orthogonal drive imaging device, wherethe target area is within reach of a probe from a targeting surface ofsaid tissue, said method comprising: (1) establishing a lower planesubstantially at the surface of said tissue, the lower plane comprisinga lower vector point, and the lower plane portion comprising a lowerplane template comprising a pair of angled members of animager-conspicuous material, each of said pair of angled membersdefining an angle of about 53 degrees; (2) establishing an upper planeabove the surface of the tissue, the upper plane comprising an upperplane template comprising a pair of adjacent angled members comprisingan imager-conspicuous material, the pair of adjacent angled membersaligned such that the pair of adjacent angled members open insubstantially parallel directions, and wherein the angle defined by eachof said pair of adjacent angled members defines an angle of about 53degrees, (3) providing an alignment structure comprising an upper vectorpoint adapted to move parallel to said upper plane, so as to be able todefine a vector passing through said upper and lower vector points; (4)if not so aligned, aligning the upper plane and lower plane templatessuch that the image plane of the imaging device is aligned perpendicularto the bisectors of each of the adjacent angled members; (5) determiningthe position of the target area with respect an entrance point throughthe lower plane template, (6) adjusting the alignment structure so as toform a vector containing said entrance point and a point in said targetarea; and (7) passing the probe along said vector to the target area.

The device and methods of the present invention may be used with anydiagnostic or clinical imaging device, such as MRI, CT, radiographic orfluoroscopic devices. The device and methods of the present inventionmay also be used with industrial imaging devices in fields even outsideof life sciences and medicine.

The device of the present invention is based on a unique image patternthat encodes exact dimensional information (e.g., in mm) on each imagethat is directly related to the identical dimensional positions (e.g.,in mm) in real-time and 3D space. This means there is no need forcomputers or any other type of complex translation of the imageinformation to utilize data in the real-time space of the image system.

For example, if the image generated by the device depicts two dotsseparated by 41 mm, this means that image section plane is crossing theimage conspicuous pattern of the device at a line labeled 41 mm on thedevice in real-space.

In a real-time environment, the visual cues generated by thedevice-generated pattern lead the operator to an exact real-time spacelocation without the need of special computer information. For example,if the operator is moving the correct direction, the pattern displayspoints converging. If the operator is moving the wrong direction, thepoints diverge.

The pattern generated by devices of the present invention, in itspreferred embodiment, is based on a specific geometric oddity. Atriangle formed in a square has this property when the base of thetriangle is the base of the square and the apex of the triangle is themidpoint of the top of the square. The triangle formed in this specificsituation is a special isosceles triangle of about 53 degrees. Thepattern of the preferred inventive device uses the limbs of thistriangle. The limbs of the preferred device pattern are made of imageconspicuous materials.

When the imaging section plane is parallel to the pattern it produces aset of unique imaging and real-space characteristics.

The true distance between the limbs of the device image conspicuouspattern as measured on the image is equal to the true distance from theintersection of the pattern limbs. There is no need for a computer totell the operator when this occurs or for complex calculations. Theslice location is encoded as a true linear measurement on the image.

The distance from a limb of the device's image conspicuous pattern to avector line measured on the image can be used to define the same pointin real-space on the device.

FIG. 4 shows examples of the stereotactic pattern generated by a devicein accordance with one embodiment of the present invention.

The “V” shapes represent the device-generated pattern. The angle of the“V” shape should preferably be about 53 degrees.

The device pattern has a unique characteristic. The distance between thelimbs (horizontal arrows 8) of the pattern measured on the image whenthe slice symmetrically crosses the pattern (parallel to the base of thetriangle) is equal to distance from the intersection of the two limbs(i.e., the distance along vertical arrows 9). Note that independent ofwhere the image slice crosses the pattern, the distance from theintersection of the two limbs is encoded on the image by the patternbeing of an image conspicuous material. This relationship allows forimmediate exact definition of the location of the section plane inreal-space on the pattern using only this simple image information.

For instance, when using CT, each limb of the “V” may be made of animage conspicuous material such as wire. In the case of MRI, tubes(typically non-metallic; plastic) filled with contrast enhanced fluidmay be used as pattern limbs. The pattern may also be drawn directly onthe patient, or included on an imager transparent material attached tothe patient, such as through the use of adhesives. Examples may includea piece of flexible material, such as Mylar, provided with an adhesiveon one side and bearing an image conspicuous pattern (provided in theform of an attached image conspicuous object in the shape of the “V”, orin the form of a printed design in the shape of the “V” in accordancewith the present invention). Another example may be an adhesive strip,similar to an adhesive bandage, and provided with image conspicuousmaterial members attached thereto, or an image conspicuous “V” patternprinted thereupon.

FIG. 5 shows a view of two V-shaped patterns adjacent to each other,forming a “W”-like pattern. The two upwardly-opening triangles representthe necessary image-conspicuous components of the present invention. Thepattern is sectioned at various planes. The image plane is parallel tothe base of the pattern. Section A is at 30 mm, B is at 10 mm and C isat 0 mm in relationship to the pattern. The images produced at eachsection are shown in FIG. 6.

FIG. 6 is a view of the image perspective of each slice shown in FIG. 5.This view, and that shown in FIG. 5, shows how the points on the imagediverge with the true distance of the image section plane from the baseof the pattern (such as the distance of planes 11A, 11B or 11C from theintersection of the “V” limbs). For instance, section 11A is at 30 mm,11B is at 10 mm and 11C is at 0 mm in relationship to the pattern. Whenthe distances between the image plane intersection points 14 of eachpair of “V” limbs are equal, the image planes 13 are determined to beparallel to the base of the pattern (i.e., perpendicular to thebisectors of the two “V” angles).

The distance between each limb of the pattern encodes the slice locationin millimeters in the same dimension on the pattern as is seen on theimage. The distance between the points on each “V” is identical,confirming that the image plane is parallel to the device. With thisinformation, a plane on the pattern can be found or the image slice canbe moved to a precise position in relation to the pattern. For example,if the distance between the intersection points of the image plane 13with the limbs of each V was 10 mm, but the operator wanted to move thepatient to the 30 mm line on the device, the operator would know howmany millimeters, and also in which direction to move the table on whichthe patient may rest. Likewise, the operator may also move the intendedinsertion point of a medical device, such as a needle, diagnostic probeor any other therapeutic apparatus (such as any object, directed matteror light) that may be directed toward the target point along a vectordetermined by the device of the present invention.

Thus, one of the fundamental features of the device is that it providesa three-dimensional alignment template that resides at a distance fromthe identified target point without having the target point locatedwithin the space defined by the three-dimensional alignment template.This allows the three-dimensional alignment template to be repositionedand to function accurately even if the tissue or patient has moved. FIG.6 a is a graphical representation of a demonstration of these optionalangulation properties. Two V patterns are shown with various parallelsection planes shown crossing the device pattern. The distance betweeneach V (V1 and V2) is labeled for each image section. Note that thelinear distance measurement differences between these two is always thesame. In this case, V1-V2 equals −7. The value is related to the anglethat the slice and pattern define with their intersection, and it isindependent of the location of the section. The sign (positive ornegative) encodes which direction the pattern must be rotated to achievealignment. The value and sign are printed on the device; similar to adegree scale (in V1-V2 units), so the operator may rotate the device tothe precise parallel position from a single image acquisition. This isdone at the beginning of each procedure to confirm appropriatepositioning of the device.

FIG. 6 b shows a graphical representation of a diagram illustratingmathematical difference between V1 and V2 (on the right) and theincreasing mal-alignment in degrees (on the left) of the image plane tothe pattern. It should be noted that V1-V2 is not a simple function ofdegrees, but is more complex. The actual degree scale in V1-V2 valuesmay be printed on the device for accurate rotation of the device patternto the section plane.

FIG. 7 shows a plan and a perspective view of the device-generatedpattern. The points on the image diverge with the true distance of thepattern formed by the intersection of V1 and V2 with the image sectionplane 13, as seen by reference to the dots showing the intersectionpoints of the image plane 14 appearing in the image view, and comparingthis view to the geometry shown in FIG. 6. FIG. 7 a shows a plan and aperspective view of the device-generated pattern.

The section plane has been moved to a position closer to the top of theW formed by the two “V” patterns. In the bottom figure, it can be seenthat the section plane 13 intersects V1 and V2 such that the points ofintersection 14 are further apart. When aligned so that the distancesbetween the intersection points of each “V” are the same, the distancebetween the intersection points 14 of each “V” corresponds to thedistance of the section plane from the plane containing the points ofintersection of the limbs of the two “V” figures. The distance may berepresented on a scale that may be printed on the device to provide forprecise localization in real time without the need for computerinformation.

FIG. 7 b shows a plan and a perspective view of the device-generatedpattern, as it would appear when the section plane and the pattern ofthe device of the invention are not parallel. This view shows that theintersection points 14 of the section plane 13 on V1 are closer togetherthan those points where the section plane 13 intersects V2. Thedifferences between these two distances can be used in calculations thatallow the device to be quickly aligned with the section plane.

FIG. 8 shows a view of two V-shaped patterns 10 (also designatedseparately V1 and V2) adjacent to each other, forming an “M”-likepattern, to illustrate the operation of a device in accordance with thepresent invention. The triangles represented by these V's are portionsof the device pattern that represent the required image conspicuouscomponents of the device pattern (other portions may be made imageconspicuous as desired). The two-V pattern allows the operator todetermine whether the device is parallel to the image plane 13 byassuring that the intersection points of the image plane 13 with therespective limbs of V1 and V1 are equidistant.

The pattern is preferably ruled so as to section the device scales atvarious planes 11 along at least one axis of the device pattern,preferably perpendicular to the bisectors of V1 and V2, so as to providea measure of the distance from one edge of the device pattern (i.e.,where the legs of each V intersect) to the opposite edge. This providesa reference template to locate a target point (i.e., target point 12)within the imager view and with respect to the legs of the V scales 15.

The pattern may also include multiple smaller “V” scales 15 of similargeometry as shown in FIG. 8. These additional patterns are designed sothat the distance from any of the other principal “V” limbs can bedetermined. In the embodiment shown in FIG. 8, the multiple smaller “V”pattern scales 15 are spaced such that they represent increments ofmillimeters.

FIG. 8 also shows the preferred circular shape imposed with respect tothe device pattern, and the graduated scale 16 that measures the degreeto which the device pattern may be non-aligned with the image section.This graduated scale is expressed in terms of V1 minus V2, representingthe difference of the distance between the image plane intersectionpoints on V1 and the distance between the image plane intersectionpoints on V2.

FIG. 8A shows a CT plan view of a device pattern, showing the imageslice location 13 and target point 12 located, in this example, 41 mmfrom the base of the image pattern (i.e., the line where the legs ofeach V intersect; determined by knowing the distance between theintersection points of the image plane with the legs of one of the Vs).This value may be read from the linear scale 17 provided along the sideof the rectangle enclosing the dual V pattern. In the position shown inFIG. 5A, the distance from the inner V limb of V1 (i.e., the V withinwhich the target point is found) is 13 mm. This distance may bedetermined by referencing the target point as it appears between thelimbs of two of the smaller Vs, within the principal V1 pattern, thatrepresent, respectively, 10 and 20 mm from the inner V limb of V1.(i.e., the target point is about 13 mm from the inner limb of V1).

FIG. 9 shows the operation of the graduated scale 16 that measures thedegree to which the device pattern may be non-aligned with the imagesection. In this example, the image on the left shows that the devicepattern is displaced with respect to the image plane, indicated by theV1 distance being 19 mm and the V2 distance being 31 mm. The graduatedscale shown below the device pattern is expressed in terms of V1 minusV2, representing the difference of the distance between the image planeintersection points on V1 and the distance between the image planeintersection points on V2. In this case, the device pattern is rotatedby negative 12 units to bring, easily and quickly, the device patternparallel to the image plane (as shown in the image on the right of FIG.9). The measured distance is independent of the slice thickness.

The pattern is preferably mounted onto a circular base so it can berotated parallel to the section plane as directed, for instance, byreference to the circular graduations shown in FIGS. 8, 9, 11 and 15that may be provided on a portion of the base or frame about which thetwo-V bearing template frame may be rotated.

The images produced at each section are shown in the FIG. 10. In thisexample, the target point is 13 mm to the right of the left limb of theV1 pattern at the 41-mm line from the intersection point of the limbs ofthe “V”s (note radiology right-left standard labeling). The image planeis centered at the 41-mm line. The lines parallel to the imageconspicuous device pattern may be used to find the precise point on thepattern in real-space. These are not visible on the image.

The image on the upper right of FIG. 8A is a scout plan image of thesame pattern. The two pattern limbs (“V”s) are seen and the circleencloses the target point. The image plane intersects the pattern at the41-mm line, and this distance is the same as that from the intersectionof the two limbs. FIG. 10 shows an image perspective of the same patternand target point seen in FIG. 8A (plan view on the left and real-spaceview on the left). Each “V” pattern limb is labeled. The demonstrationtarget point is seen as a vertical density. The circle shows the targetpoint. The distance measured on the image between each of the limbs ofthe V's is 41 mm, defining the location of the image plane on the devicepattern. The target point is 13 mm to the right of the left limb of theright V1 pattern. Using this precise information, it is possible toplace a small disc directly over the target despite the fact that thetarget is hidden from the view of the operator.

A small wire may be imbedded into a foam base below the opaque patternto act as a point target for demonstration purposes as seen in FIGS. 8Aand 10. The target point is centered in the small circle shown in theimage.

FIG. 11 is an image view of a localized target point. FIG. 11 shows aview of the target point that has just been localized with a smallplastic disc marker 17 placed over the target point in real-space atreal-time in the scanner. This example shows that the localization ofthe target point with a high degree of accuracy. A skilled operatoraccomplished this localization in only a few minutes. Two smalldensities of the disc are seen directly overlying the target point. Thedisc was set at the 41-mm image section line and 13-mm from the leftlimb of V1. This is a simple example that confirms the speed andaccuracy of a device of the present invention.

FIG. 12 shows image perspectives showing an example of how a device ofthe present invention, and the image information, is used in an actualimaging setting. The image on the left of FIG. 12 is a CT cross-sectionof the “V” pattern of the device shown earlier. The distance between thelimbs of V1 is 19 mm (the smaller line on the left), and the distancebetween the limbs of V2 is 31 mm (the longer line on the right). It isclear that the device is not parallel to the image plane. The differenceof V1 and V2 is −12 units. If the device is rotated this indicateddegree and direction, the next image will be parallel to the imageplane.

The image on the right of FIG. 12 is the plan view (real-space) of thepattern. It should be noted that it is clear that the section plane isnot parallel to the pattern. The distances between the limbs of both V1and V2 are shown as lines parallel to the section plane. A small targetpoint is seen as a dot along the slice location.

Generally, devices in accordance with present invention may be accurateto within 1 or 2 units (i.e., mm or less) of the limits of the imageresolution. These levels of accuracy may be achieved independent of thesection thickness and orientation.

When an instrument is attached to a pattern device of the presentinvention, its position may be encoded independent of the slicethickness. Accordingly, partial volume artifact vector errors may beeliminated. The relationship of the instrument to the image may beencoded, a capability not possessed by known prior art devices.

FIG. 24 shows a stereotactic device of the present invention comprising:a frame portion attached or perpendicular to: (a) a lower plane portiondefining a lower plane; and (b) an upper plane portion comprising atemplate defining an upper plane and comprising a pair of adjacentangled members comprising an imager-conspicuous material, the pair ofadjacent angled members aligned such that the pair of adjacent angledmembers open in substantially parallel directions, and wherein the angledefined by each of said pair of adjacent angled members defines an angleof about 53 degrees; the frame portion being open on one side so as toallow an object passed through the alignment structure to be removed ina direction substantially parallel to the upper plane.

The lower portion may comprise a template comprising at least one pairof angled members of an imager-conspicuous material, at least one angledmember defining an angle of about 53 degrees. The frame portion may beadapted to rotate said upper and lower plane portions with respect to anaxis perpendicular to the upper and lower planes. The frame portion mayadditionally comprise a graduated position scale to indicate the degreeof rotation of the upper and lower planes with respect to one another.The lower portion may additionally comprise an adhesive base portion.The alignment structure of the upper portion may be perforable such thatat least portions of a medical instrument may be passed. The adjacentangled members may further comprise a graduated linear distance positionscale.

FIG. 13 shows an image perspective and graph showing the actual resultsof 10 point localizations with CT using a device of the presentinvention. In 95% of the cases the pattern was within 1.5 mm of theactual location. This has not been achieved through known simplesterotactic devices. When utilizing most CT imagers, the operator isable to actuate a laser positioning system to help localize the slicelocation. This can be helpful, but many times it may be inaccurate or oflittle value with live procedures because the light is obstructed. Theselaser-positioning systems are also frequently ineffective since theoperator cannot work inside the bore of the system when the light is onto take advantage of its localizing capability. In MR systems, the laserpositioning lighting systems are of even less value since they onlydefine one or two limited planes. In fluoroscopic systems, the devicemay be used in accordance with the real time display, and thus it maynot be necessary to use the device gradations, but instead, the devicemay still be used with its remote actuator while viewing the real timeimage.

In order to align the device with the section plane with sufficientaccuracy and confidence, the device of the present invention may use itspattern to simultaneously encode the exact angle of alignment with theimage plane in units that are printed on the pattern device for properimage section plane orientation. Based on the reading of these units,the operator may either rotate the device into alignment with thesection plane or the plane may be rotated parallel to the device.

The ability of the device of the present invention to align the patternto the image plane is possible because it is based on a number of uniquemathematic and geometric relationships.

Independent of the location at which the section plane crosses thepattern, the mathematical difference between the dimensions in mm of thetwo V patterns (V1 minus V2) is a constant. Also, the mathematicaldifference between the distances of V1 and V2 (V1-V2) is constant forany slice at the same orientation to the pattern.

The mathematical difference between the distances of V1 and V2 (V1-V2)is proportional to the angulation of the section plane and the pattern.

This angle may be printed on the device in units of V1-V2 to enable theoperator to rotate the device to the section plane for alignment. WhenV1-V2=0, then the pattern is parallel to the image section plane. Thesign of V1 minus V2 (positive or negative) defines the direction ofangulation (clockwise, counterclockwise). Either the section plane canbe rotated to the pattern, or the pattern can be rotated to the sectionplane.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic of an enveloping frame that is used for headstereotactic systems of the prior art.

FIG. 2 is a schematic of an image obtained from a fixed frame rigidsystem in accordance with the prior art.

FIG. 3 shows an example of an MRI image showing the use of a fixed framestereotactic unit used for head imaging in accordance with the priorart.

FIG. 4 shows examples of the stereotactic pattern generated by a devicein accordance with the present invention.

FIG. 5 shows a representation of two V-shaped patterns adjacent to eachother, forming a “W”-like pattern, to illustrate the operation of adevice in accordance with one embodiment of the present invention.

FIG. 6 is a view of the image perspective of each image slicerepresentation shown in FIG. 5, to illustrate the operation of a devicein accordance with one embodiment of the present invention.

FIG. 6 a is a view of the device-generated pattern, to illustrate thegeometric basis of the operation of a device in accordance with oneembodiment of the present invention.

FIG. 6 b is a view of the device-generated pattern, to illustrate thegeometric basis of the operation of a device in accordance with oneembodiment of the present invention.

FIG. 7 is a view of the device-generated pattern, to illustrate thegeometric basis of the operation of a device in accordance with oneembodiment of the present invention.

FIG. 7 a is a view of the device-generated pattern, to illustrate thegeometric basis of the operation of a device in accordance with oneembodiment of the present invention.

FIG. 7 b is a view of the device-generated pattern, to illustrate thegeometric basis of the operation of a device in accordance with oneembodiment of the present invention.

FIG. 8 is another view of the device-generated pattern, to illustratethe geometric basis of operation of a device in accordance with oneembodiment of the present invention.

FIG. 8 a is a CT planar image view illustrating the geometric basis ofoperation of a device in accordance with one embodiment of the presentinvention.

FIG. 9 is another view of the device-generated pattern, to illustratethe geometric basis of operation of a device in accordance with oneembodiment of the present invention with regard to the rotation of thedevice to align it with the image plane.

FIG. 10 shows a photograph of an example of real-space cross-sectionalimage as defined by a device of the present invention, with thecorresponding device-generated pattern in the image, to illustrate theoperation of a device in accordance with one embodiment of the presentinvention.

FIG. 11 shows a photograph of an example of real-space cross-sectionalimage as defined by a device of the present invention, with thecorresponding device-generated pattern in the image, to illustrate theoperation of a device in accordance with one embodiment of the presentinvention.

FIG. 12 shows photographs of a cross-sectional image and a plan view ofa localized target point, illustrating the results that may be achievedwith a device in accordance with one embodiment of the presentinvention.

FIG. 13 shows an image perspective view and graph showing the actualresults of 10 point localizations with CT using a device of oneembodiment of the present invention.

FIG. 14 is an exploded perspective view of a device in accordance withone embodiment of the present invention.

FIG. 15 is a plan view of a lower template portion of a device inaccordance with one embodiment of the present invention.

FIG. 16 is a plan view of an alternative lower template portion of adevice in accordance with another embodiment of the present invention.

FIG. 17 is a plan view of an alternative lower template portion of adevice in accordance with another embodiment of the present invention.

FIG. 18 is a perspective view of a device in accordance with oneembodiment of the present invention.

FIG. 19 is a perspective view of a device in accordance with oneembodiment of the present invention, placed on a patient.

FIG. 20 is a perspective view of a device in accordance with anotherembodiment of the present invention.

FIG. 20 a is a perspective view of an alternative remote actuator thatmay be used in accordance with another embodiment of the presentinvention.

FIG. 20 b is a perspective view of an alternative remote actuator thatmay be used in accordance with another embodiment of the presentinvention.

FIG. 21 is a photograph view illustrating a step in the operation of adevice in accordance with one embodiment of the present invention.

FIG. 22 is a photograph view illustrating a step in the operation of adevice in accordance with one embodiment of the present invention.

FIG. 23 is a photograph view illustrating a step in the operation of adevice in accordance with one embodiment of the present invention.

FIG. 24 is a perspective view of an alternative remote actuator that maybe used in accordance with another embodiment of the present invention.

FIG. 25 is a photograph of an image perspective view illustrating a stepin the operation of a device in accordance with one embodiment of thepresent invention.

FIG. 26 is a photograph of an image perspective view illustrating a stepin the operation of a device in accordance with one embodiment of thepresent invention.

FIG. 27 is a photograph of an image perspective view illustrating a stepin the operation of a device in accordance with one embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

In accordance with the foregoing summary of the invention, the followingis a detailed description of a preferred embodiment of the invention,and is presently considered to be the best mode of the invention asapplied.

The device of the present invention may be made of any combination ofappropriate materials such as sterile, biocompatible materials (e.g.,plastic, wire, tubes, catheters, diaphragms, etc.).

As described in more detail below, the device of the present inventionhas three main components:

1. A lower template portion that aligns to the image plane, and isdirectly attached to the target tissue, such as a patient's skin orother surface. This component preferably has two “V” patterns withassociated mm scale patterns. It also may have a rotation correctionscale (V1-V2) printed on it. One of the “V” patterns may be removed tomake the template smaller. This component defines the point at which theprobe (i.e., instrument, light beam, etc.) enters the tissue. Thiscomponent may also help the operator keep track of the position of thetissue or patient with respect to the imaging field. It may be directlyattached to the patient, and is preferably very thin, typically about 3mm maximum.

2. A lower frame portion, such as an adhesive attached structure thatsupports the upper frame portion and helps align the upper frame portionto the lower template portion. This component may have an adhesive clearbase, and may be molded to the patient's surface. For instance, it maybe in the form of a circular sponge ring (5 mm thick) that engages theintermediate frame portion attached to the upper frame portion or otherattachments such as a table. The upper frame portion may be turned inthe lower frame portion allowing the operator to bring the upper frameportion parallel to the image plane. This component is placed in alocation between the upper frame portion and the lower template portionso that the chosen vector will be correct. In an alternative embodimentthe lower template portion may be integrated with the lower frameportion section plane.

3. An upper frame portion that supports/aligns the upper end of theprobe (i.e., instrument, light beam, matter beam, etc.) away from theskin. For instance, in the case of a needle, it may be advanced into thedevice and held by it. In a preferred embodiment, the needle may also beremoved from the device allowing for the upper component to becompletely removed. The needle could be taken out the upper componentand the upper component could be left in place. This is possible sincethe device in a preferred embodiment is open on one side. The uppercomponent has two “V” patterns. These are used to orient the operator,to confirm the relationship to the image plane as well as confirm thelocation of the needle or probe.

In a preferred embodiment there are 5 parts as described in thedrawings. The intermediate base is a clear plastic cylinder that isattached to the upper frame portion so as to support the “V” patternswith a slot. The upper frame portion has at least one (e.g., two) “V”pattern and supports the optional orthogonal motion small “V” thatactually supports the probe. This part slides back and forth in the basepart. The third part is a small “V” that has a central slit structurethat holds the needle in place, but allows the needle to be removed.This “V” also acts to confirm the location of the probe and movesorthogonal to the large “V” support, allowing for full manipulation ofthe probe to any chosen vector. In one of the described embodiments,this component slides forwards and backwards orthogonally between thetwo large “V”s.

The fourth part is the optional cable-catheter mechanism that moves thelarge double “V” pattern part horizontally.

The fifth part is the optional cable-catheter mechanism that moves thesmall “V” pattern orthogonal to the large double “V” pattern.

A sixth part is an optional handle that can be manually moved or movedwith a computer remote control mechanical system to adjust the componentfrom a distance the exact required dimensions. This part may be providedwith mm dimensions on it guiding the operator.

There are preferably two controls on the handle, one for each orthogonalmotion. There may also be an optional control to control the rotation ofthe upper frame portion with respect to the lower frame portion.

FIG. 14 shows an exploded view of a stereotactic device 20 in accordancewith one embodiment of the present invention.

FIG. 14 shows the upper plane of the device defined by an upper frameportion 22 that defines an upper plane 21 and supports a moveableportion 23 that is capable of moving in the X direction by action ofactuator 23 a. Moveable portion 23 in turn supports theimage-conspicuous members 24 that define two 53-degree V's that act asdescribed above to arrange the device to be parallel to the image plane.The moveable portion 23 also includes vertical frame portions 25 that inturn support the moveable portion 26 that is capable of moving in the Ydirection by action of actuator 26 a. Both actuators 23 a and 26 apreferably are provided with graduations accordingly with the scaleprovided on the device respectively representing the distances along theX and Y directions that the alignment aperture must be moved to align itwith the target once its position is determined from the imaging device.

The moveable portion 26 may also optionally support either anaperture-bearing material (such as within the square frame of moveableportion 26; not shown), or an aperture-bearing member 27 (having analignment aperture 27 a) that features a 53-degree V-shaped imageconspicuous portion 27 b that may also be used to align the device. Inthis embodiment, the aperture-bearing member 27 may be attached atop themoveable portion 26.

Actuators 23 a and 26 a move the upper frame portions so as to move thealignment aperture over the target vector as seen on the imaging deviceoutput. This may be done remotely through the use of a long cable suchas a flexible plastic tube that conducts a flexible plastic rod actuatorto transmit force. One controls the horizontal motion, and the othercontrols the vertical motion. The outer tube of each actuator handle isstationary. Naturally, this function may also be carried out at the siteof the device with any equivalent actuator.

The principal function of the upper frame portion is to support theV-shaped image conspicuous portion, and to provide a moveable alignmentaperture that allows an instrument, stream of matter or beam to bealigned along the determined vector 29 or its adjusted equivalent.Accordingly, the upper frame portion may be made of any clear materialappropriate to the imaging application to which it is to be applied.Examples include plastics such as PVC, Mylar, and other non-conductivematerials.

The upper frame portion 22 is attached to an intermediate frame portion28, which in this embodiment is in the form of a cylindrical section.This portion may be supplied with graduations 28 a to indicate thedegree to which the upper frame portion is out of alignment with theimage plane as described above. It is preferred that the intermediateframe portion 28 be a transparent cylindrical plastic tube section thatallows the operator to see as much of the target area from as manyangles as possible. The function of the intermediate frame portion 28 isto provide separation between the upper frame portion and the lowerframe portion. Accordingly, any one or more pieces of variousalternative geometries, such as nested sections, or a series of rods ina circular array may also provide this portion.

The intermediate frame portion 28 engages lower frame portion 30, thatoptionally includes a reference point 30 a that can be the referencepoint for the graduations 28 a, to assist the operator in reorientingthe upper frame portions to the image plane. The lower frame portion 30in this embodiment may be a plastic piece that is shaped to engage theintermediate frame portion 28 so as to allow it to rotate with respectto the lower frame portion 30. This portion optionally may be a flexiblefoam member with a releasable adhesive on its underside adapted toadhere to the target area tissue.

The lower frame portion 30 defines the lower plane 30 a upon resting onthe target tissue, and may optionally comprise a targeting templateeither integral with the lower frame portion 30 (not shown) or providedas a separate lower template piece 31 (which may also ultimately definethe lower plane 30 a). The device may have a fixative, such as anadhesive, to hold it in place against the tissue or body. The device mayalso have optional attachment strap 36 (shown in phantom) that may beattached to the lower frame portion 30, for instance, and that may beelastic, nylon, or any other appropriate material, affixed using anappropriate means such as a hook-and-loop closure, buckles, buttons,etc. The device may also have attached to it a sterile drape 37 (shownin a partially sectioned view). The sterile drape 37 may be attached tothe optional attachment strap 36, or directly to other portions of thedevice where an attachment strap is not used.

The separate lower template piece 31 has a dual 53-degree V designallowing it to be aligned with the image plane. In the displayedembodiment, the separate lower template piece 31 has a principaltemplate V FIG. 31 a centered below the center reference point of thealignment aperture 27 a. This principal template allows the operator toassess the position to which the alignment aperture 27 a must be movedto form a vector directed to the target, as described herein. Theseparate lower template piece 31 may be provided with a series ofV-shaped patterns that represent unit distances from the main V limb inthe lower template. This scale can be used with the similar scaleaccompanying one of the Vs in the upper frame portion, so that where thetarget is seen using the imaging device, the operator may determinepoints of entry through the upper and lower planes to establish a vectorto the target.

The separate lower template piece 31 may be provided with graduations 31b, if desired, to assist in aligning the template to the image plane.

The separate lower template piece 31 may itself optionally have areleasable adhesive on its underside adapted to adhere to the targetarea tissue. It may also have a perforation (not shown) between itsprincipal and secondary V design to allow the latter to be separatedfrom the former following alignment with the image plane. The separatepiece 31 in this embodiment may be made of a transparent plastic such asMylar.

The lower frame portion may also be provided with an attached steriledrape (not shown) that may be used to protect the target area fromcontamination. This may be attached through adhesives, stitching, or anyother means for attaching material to a relatively rigid part.

The separate piece 31 is also shown in FIG. 15. This separate templatepiece may be used for a CT imager, and may be made with imageconspicuous materials, such as image conspicuous inks or paints that maybe printed or silk-screened upon the surface, or that may be formed intothe article itself (such as a piece of metal molded into a plasticpiece). The pattern on the separate piece 31 preferably has a principalV design 31 a and a secondary principal V design 31 c. This device mayalso have a perforation along perforation line 31 d to allow thesecondary principal V design 31 c to be separated from the principal Vdesign 31 a.

An alternative separate piece, shown in FIG. 16, for use as the lowertemplate may be an adhesive bandage-style strip 32 bearing imageconspicuous members forming a 53-degree V figure with optional rulings32 a showing the distance from the base of the V (as described above),with targeting cross-hairs and a target aperture 32 b. This type oftemplate is appropriate for MRI use where the tubular members are filledwith an image conspicuous material.

Another alternative separate piece for use as the lower template isshown in FIG. 17, and may be an adhesive bandage-style strip 33 bearingan image conspicuous pattern forming a 53-degree V figure with optionalrulings 33 a showing the distance from the base of the V (as describedabove). This type of template may be printed with image conspicuousmaterial similar to that shown in FIG. 15.

FIG. 18 shows the device shown in FIG. 14 (without item 31, theattachment strap and the sterile drape) in an assembled configuration.FIG. 18 shows an instrument such as a syringe 34, placed throughalignment aperture 27 a. FIG. 18 also shows intermediate frame portion28 fitted into lower frame portion 30. Actuators 23 a and 26 a move theupper frame portions so as to move the alignment aperture over thetarget vector as seen on the imaging device output.

FIG. 18 also shows an optional additional actuator 38 that is mountedonto lower portion 30 and is attached so as to allow the intermediateframe portion 28 to be rotated with respect to the lower portion 30, andworks in the same way as actuators 23 a and 26 a, except that thestationary outer sleeve of the actuator is attached to the lower portion30 while the moveable inner core is attached to the frame 28. Thisallows remote alignment of the upper plane portion with the image plane.The actuator 38 may also be provided with graduations indicating therequired distance of rotation to bring the device parallel to the imageplane, such as may accord with the reading obtained from graduations 28a.

FIG. 19 shows an alternative lower portion and attachment variation inthe stereotactic device 20 (shown attached to the head of a patient),otherwise the same as that shown in FIGS. 14 and 18. FIG. 19 shows lowerframe portion 35 (a mating piece of cylindrical plastic) in place oflower portion 30 shown in FIGS. 14 and 18. Lower frame portion 35 asshown may be attached to a device such as an elastic band 36 to hold thedevice 20 in place (with frame portion 28, and the balance of the deviceas shown in FIGS. 14 and 18). This may be done through use ofappropriate adhesives, or stitching the elastic onto the lower frameportion 35 through holes provided along its bottom (not shown). Anaperture is provided in the elastic band or other attachment means, topermit access to the target area through it. Preferably, the elasticband is in turn attached to a sterile drape 37 that may be used toprotect the target area from contamination.

An alternative remote control actuator 50 (which is a double actuatorsimilar to the 23 a/26 a actuator described above) is shown in FIGS. 20a and 20 b. This type of actuator features an outer sleeve such as 51,and an inner screw 52. The outer sleeve 52 has an engagement structuresuch as extension 53 that engages the threads of screw member 52. Theextension member 53 also has the property that its engagement with thethreads of screw member 52 may be overcome by direct linear movement.This will normally be brought about through the use of loose tolerancesin the engagement, or through the screw or extension member or bothbeing of sufficiently flexible material to allow the threadingengagement to be overcome, and the screw and sleeve moved directly withrespect to one another. As an alternative to the structure shown inFIGS. 20 a and 20 b, the extension member may extend directly into thehollow sleeve from one of its interior surfaces.

In a preferred embodiment, the threads of the inner screw are preferablychosen so as to accord with a given distance measurement (such as 1 mmdistance between threads), and so each turn of the inner screw accordswith a respective partial distance measurement, e.g., one half turnequals ½ mm distance.

This actuator allows the operator to sense a tactile and/or audiblefeedback with the direct movement of the inner screw within the outersleeve when movement of the upper alignment portion is needed; and toeasily move the actuator a fraction of the distance measurement forrefinement of position by turning the inner screw 1/nth of a turn toapproximate an additional fractional distance measurement.

It will be appreciated that the optional remote control actuator(s) usedin accordance with the present invention may be any alternativeactuating means, such as hydraulic or servo actuated, etc.

FIG. 20 shows an alternative architecture for the upper and intermediateframe portions of the device shown in FIGS. 14 and 18. This deviceportion may be used with any of the above-described features notinconsistent with its function described below.

FIG. 20 shows the upper plane 41 of the device defined by an upper frameportion 42 that supports a moveable portion 43 that is capable of movingin the X direction by action of actuator 43 a (that uses the sametubular type plunger actuator). Moveable portion 43 in turn supports theimage-conspicuous members 44 that define two 53-degree Vs (i.e., formedfrom wires imbedded in or otherwise held within or adhered to a plasticplanar member; i.e. for use with a CT imager) that act as describedabove to arrange the device to be parallel to the image plane. Themoveable portion 43 also includes vertical frame portions 45 that inturn support the moveable portion 46 that is capable of moving in the Ydirection by action of actuator 46 a. In this embodiment, the moveableportion 46 is made up of two flexible plastic pieces 46 b and 46 c thatcooperate to form an aperture-bearing member 47 (having an alignmentaperture 47 a) that may also feature a 53-degree V-shaped imageconspicuous portion 47 b that may also be used to align the device. Theflexible plastic pieces allow the needle or probe to be pushed throughthe device without changing the vector.

The two flexible plastic pieces 46 b and 46 c are sufficiently flexibleto allow the needle device to be moved laterally (i.e., along vector Y)with respect to an instrument once placed through the alignment aperture47 a. The flexible plastic pieces 46 b and 46 c may also be providedwith image-conspicuous members 46 d and 46 e, respectively, similar toimage-conspicuous members 44 to define another “V” pattern for alignmentpurposes.

The intermediate frame portion 48 also may be provided with an openingin the same direction to allow the device to be moved laterally. Thisdesign permits the device to be moved from around an instrument once theinstrument is placed into the target. This feature is particularlyuseful in applications where an instrument is placed in soft tissue of apatient where it would be disadvantageous to maintain the instrumentimmobilized (i.e., in the alignment aperture) once placed into thetarget tissue while the patient is breathing. This feature generallyallows the operator to remove the device from the patient once theinstrument has been placed in the target for greater visibility andmobility.

Actuators 43 a and 46 a move the upper frame portions so as to move thealignment aperture over the target vector as seen on the imaging deviceoutput. This may be done remotely through the use of a long cable suchas a flexible plastic tube that conducts a flexible plastic rod actuatorto transmit force in the manner of a cable-catheter mechanism.Naturally, this function may also be carried out at the site of thedevice with any equivalent actuator or manual movement.

In order to operate the device of the present invention, the followingsteps preferably may be followed:

1. The patient is imaged and the target is found.

2. A non-sterile pattern similar to or identical to the base componentis placed on the skin approximately at the entry point.

3. Another image is acquired.

4. The relationship of the image plane to the pattern is measured.

5. If the pattern is not parallel then it is rotated based on therotation correction scale.

6. Another image is made to confirm the pattern is parallel.

7. If parallel, then the entry point is found by drawing a vector on thecomputer screen.

8. The entry point location may be localized on the pattern and the skinmay be marked (ink) at that point.

9. The skin preferably is prepared for sterile handling and treatment.

10. A sterile lower pattern is placed over the entry point parallel tothe section plane. This is done by measuring the V1 and V2 image planeintersection distances to confirm that they are the same.

11. The needle is pushed through the sterile base pattern at the desiredentry specific point (for example where the distance on the patternmeasures (14 mm)) and is then removed.

12. The skin may be numbed to anesthetize at the chosen point of entry.

13. The upper and intermediate frame portions are attached to thepatient so that the chosen vector will be correct for the target, theentry point, and the upper component's range of motion, the needle isplaced in the upper support.

14. The upper frame portion/intermediate frame portion combination isthen placed in the corresponding lower frame portion ring and isoriented parallel to the image plane.

15. An image is acquired to confirm that everything is aligned.

16. The vector is drawn on the image through the needle entry point.

17. The upper component is then moved to correct dimensions to confirmthat the needle is pointing at the target, by remote control.

18. The needle is then confirmed to be in the correct vector positionoutside the patient and the distance to the target is measured.

19. The needle may then be pushed to the target using local anesthetic.

20. The needle position in the target may then be confirmed by imaging(where the FIG. 20 embodiment is used, the open architecture allows theoperator to remove the upper plane portion and supporting frame once thetarget has been reached, allowing the operator to proceed with theprocedure unobstructed by the device).

21. The upper component can be removed.

22. The procedure is completed, such as through administration ofmedication or removing tissue for biopsy.

23. The needle is removed or the rest of the components are removed asdesired.

In FIG. 21, the target point for entry is found and the probe is placedat a standard position through the lower template pattern 31. In thiscase it is at the 24-mm line.

In FIG. 22, the lower frame portion 30 is then placed in the correctlocation to support the intermediate and upper frame portions 28 and 22.

In FIG. 23, the upper and intermediate frame portions 22 and 28 are putin the lower frame portion 30. This may be done either by sliding thedevice over the needle through an open slot in the device as provided inthe embodiment of FIG. 20, or by temporarily removing the needle, andreplacing the needle through the alignment aperture 27 a in theembodiment of FIGS. 14 and 18. The upper frame portion may then bemanipulated by remote control to the correct vector, and then the needleis pushed to toward the target.

FIG. 24 shows an exploded view of a stereotactic device 120 inaccordance with one embodiment of the present invention.

FIG. 14 shows the upper plane of the device defined by an upper frameportion 122 that defines an upper plane containing an upper templatepiece 131 with a dual 53-degree V design 131 a allowing it to be alignedwith the image plane as described above.

The principal function of the upper frame portion is to support theupper template piece, which is preferably perforable or transparent toallow an instrument, stream of matter or beam to be inserted or passedthrough and aligned along the determined vector. Accordingly, the upperframe portion may be made of any clear material appropriate to theimaging application to which it is to be applied. Examples includeplastics such as PVC, Mylar, and other non-conductive materials.

The upper frame portion 122 is attached to an intermediate frame portion128, which in this embodiment is in the form of a cylindrical section.This portion may be supplied with graduations 128 a to indicate thedegree to which the upper frame portion is out of alignment with theimage plane as described above. It is preferred that the intermediateframe portion 128 be a transparent cylindrical plastic tube section thatallows the operator to see as much of the target area from as manyangles as possible. The function of the intermediate frame portion 128is to provide separation between the upper frame portion and the lowerframe portion. Accordingly, any one or more pieces of variousalternative geometries, such as nested sections, or a series of rods ina circular array may also provide this portion.

The intermediate frame portion 128 engages lower frame portion 130, thatoptionally includes a reference point 130 a that can be the referencepoint for the graduations 128 a, to assist the operator in reorientingthe upper frame portions to the image plane. The lower frame portion 130in this embodiment may be a plastic piece that is shaped to engage theintermediate frame portion 128 so as to allow it to rotate with respectto the lower frame portion 130. This portion optionally may be aflexible foam member with a releasable adhesive on its underside adaptedto adhere to the target area tissue.

The intermediate frame portion 128 and upper frame portion 122 may beprovided with an opening to allow the device to be moved laterally. Thisdesign permits the device to be moved from around an instrument once theinstrument is placed into the target. This feature is particularlyuseful in applications where an instrument is placed in soft tissue of apatient where it would be disadvantageous to maintain the instrumentimmobilized (i.e., in the alignment aperture) once placed into thetarget tissue while the patient is breathing. This feature generallyallows the operator to remove the device from the patient once theinstrument has been placed in the target for greater visibility andmobility.

The lower frame portion 30 defines the lower plane upon resting on thetarget tissue, and may optionally comprise a targeting template eitherintegral with the lower frame portion 30 (not shown) or provided as aseparate lower template piece 31 (which may also ultimately define thelower plane). The device may have a fixative, such as an adhesive, tohold it in place against the tissue or body. The device may also haveoptional attachment strap 36 (shown in phantom) that may be attached tothe lower frame portion 30, for instance, and that may be elastic,nylon, or any other appropriate material, affixed using an appropriatemeans such as a hook-and-loop closure, buckles, buttons, etc. The devicemay also have attached to it a sterile drape 37 (shown in a partiallysectioned view). The sterile drape 37 may be attached to the optionalattachment strap 36, or directly to other portions of the device wherean attachment strap is not used.

The separate lower template piece 31 has a dual 53-degree V designallowing it to be aligned with the image plane. In the displayedembodiment, the separate lower template piece 31 has a principaltemplate V FIG. 31 a centered below the center reference point of theupper template piece. The separate lower template piece 31 may beprovided with a series of V-shaped patterns that represent unitdistances from the main V limb in the lower template. This scale can beused with the similar scale accompanying one of the Vs in the upperframe portion, so that where the target is seen using the imagingdevice, the operation may determine points of entry through the upperand lower planes to establish a vector to the target.

The separate lower template piece 31 may be provided with graduations 31b, if desired, to assist in aligning the template to the image plane.

The separate lower template piece 31 may itself optionally have areleasable adhesive on its underside adapted to adhere to the targetarea tissue. It may also have a perforation (not shown) between itsprincipal and secondary V design to allow the latter to be separatedfrom the former following alignment with the image plane. The separatepiece 31 in this embodiment may be made of a transparent plastic such asMylar.

The lower frame portion may also be provided with an attached steriledrape (not shown) that may be used to protect the target area fromcontamination. This may be attached through adhesives, stitching, or anyother means for attaching material to a relatively rigid part. FIGS.25-27 show the stepwise use of a device in accordance with the presentinvention when used on a live subject in conjunction with an imagingdevice.

In another example of the device's application, it may be used inconjunction with a fluoroscope. In fluoroscopy, the operator views thetissue and the target in the same fashion as watching a television. Thelower plane image is placed over the target, and the end of the probe(i.e., such as a needle) is positioned over the target live in realtime. At this point, the skin may be anesthetized. The upper planeportion of the device is then placed over the target site (with theoptional drape and support base). The probe is then placed at the targetskin entry point and the upper plane portion would be aligned. The otherend of the needle is placed in the alignment structure (whether usingeither the FIG. 18 or 20 embodiment). Another fluoroscopic image is thenacquired to find the target. By remote control, the upper supports aremanipulated orthogonal drive until the probe is seen as just a dot (theprobe at this point being parallel to the target vector).

The fluoroscope can then be adjusted to a different angle and theoperator can view the image in real time as the probe is advanced towardthe target. Where the FIG. 20 embodiment is used, the open architectureallows the operator to remove the upper plane portion and supportingframe once the target has been reached, allowing the operator to proceedwith the procedure unobstructed by the device.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims, which are incorporated herein byreference.

1. An alignment article for use with an imaging device, said alignmentarticle comprising an imager-transparent member bearing animager-conspicuous material in the shape of at least one angle of about53 degrees.
 2. An alignment article according to claim 1 wherein saidalignment article is planar and additionally comprising adhesive base onone side thereof.
 3. An alignment article according to claim 1 whereinat least one angle additionally comprises a graduated linear distanceposition scale perpendicular to its bisector line.
 4. An alignmentarticle according to claim 1 wherein said alignment article is planarand said imager-conspicuous material is in the shape of two angles eachof about 53 degrees and open in substantially parallel directions, andadditionally comprising a perforation in said article passing betweensaid two angles.
 5. An alignment article according to claim 1 whereinsaid alignment article comprises a material capable of being perforatedby a syringe needle.